Shiva Purana
प्रातः सूर्यानुवाकेन सायमग्न्यनुवाकतः । अपः पीत्वा तथामध्ये पुनः प्रोक्षणमाचरेत् २५ ।
He shall drink by way of Ācamana reciting the mantras from Sūryānuvāka in the morning or from Agni-Anuvāka in the evening and perform the ceremonial sprinkling in the middle.
english translation
prAtaH sUryAnuvAkena sAyamagnyanuvAkataH । apaH pItvA tathAmadhye punaH prokSaNamAcaret 25 ।
hk transliteration by Sanscript